docs: def select(self, sql):
          """
          Execute arbitrary SQL select query against the database
          and return the results.
  
          :param sql: SQL select query to execute
          :type sql: string
          :returns: SQL select query result
          :rtype: list of lists
          :raises: MySQLdb.Error
          """
          cursor = self.connection.cursor()
          try:
              cursor.execute(sql)
              results = [list(i) for i in cursor.fetchall()]
          finally:
              cursor.close()
          return results